Field of the Invention
The present invention relates to a jib attachment/detachment mechanism for detachably attaching a jib on a tip portion of a boom.
Description of the Related Art
Conventionally, an attachment/detachment mechanism for detachably mounting a jib support provided to a rear portion of a jib main body on a boom head provided to a tip of a boom has been known (see Japanese Patent Application Publication No. 2000-153992).
In such an attachment/detachment mechanism, a cylinder for attachment and detachment is provided to the jib, a movable sheave is provided to a movable side of the cylinder for attachment and detachment, and a fixed sheave is provided to a base end portion of the jib. When the cylinder for attachment and detachment extends, the movable sheave is moved in the extension direction to pull wires. Thus, the fixed sheave is pulled up, and the jib is mounted onto a tip portion of the boom.
However, the attachment/detachment mechanism has a problem of requiring provision of a dedicated attachment/detachment cylinder for mounting the jib support on the boom head.